Gear-cutter



W; .T. SEARS.

GEAR CUTTER. awn-acme mm .mm mum.

1,392 36 Patented Oct. 4, 1921 INVENTOR WM 7'? 6M J TYRNEY UNITED s'nrri-zs PATENTOFYFICE.

WILLARD m. snnns,

noun conmnv, or

Application filed March 17, 1919.

To all whom it may concern:

OF. MONICLAIR, N NEW YORK, N.

EW JERSEY, ASSIG-NOR Y., A CORPORATION OF NEW JERSEY.

Specification 01' Letters Patent.

I, WILLARD T. SEARS, ed States, residing at Essex and State have invented certain new vements in Gear-Gutters,

is a specification.

cutter of the axially reciprocating tooth-curve-generating type,

contour which i of the same pitch diameter.

the invention 1s teeth which are adjustable so the cutter having an effective 5 the same as that of a gear The object of to provide a cutter having as to maintain the pitch diameter of the cutter the same notwithstanding reduction 0 grinding for the pur In the accompany shown mg the embodiment of to be illustrative only and is drawing f the teeth by sharpening.

I have the invention deem preferable, but it will the draw.

ing is intended not to be construed as defining or limiting the scope of the invention,the accompanying claims be-.

ing

Fig.

body p series 0 Each tooth 2 is provi ting face 3 which is perpe stantially perpendicul cutter.

relied upon for that purpose. Of the drawing: Figure 1 is a plan view .of a cutter embodying the invention.

2 is a vertical sectional view taken of Fig.

Fig. 2.

to the drawing, 1

d 2, 2 a circular horizontal sectional view taken represents the f cutting teeth carried by the body.

ar to I Preferably slightly inclined with respe 'pendicular,

suitable rake. lieved upward and and is provid face,

with an e that of relief faces lines extending upward and inward the edges of the cutting face.

as shown,

Each tooth ifective shalp a gear tooth l, 4 and seen that while the effective cutting tooth. correspon tooth, the actual shape a of intersection of the face 3.

ds to is slightly di inclination of the the cutting so as nward from ed at the cutting face ecorresponding to referably the lateral. 5 are formed of straight ded with a bottom outndicular or subthe axis 0 f the face is ct to the perto provide a is suitably rethe cutting from It will be shape'of each that of a gear t a horizontal plane fl'erent because bottom cutting The actual cross-sectional shape is the lower main portion of the body.

Serial No. 283,170.

the same at all horizontal planes, and the effective shape therefore remains unchanged after grinding, provi the cutting face is keptthe same.

The several cutting teeth 2 are-suitably mounted on the body 1 and are equally spaced so as to provide a composite effective contour which is substantially the same as that of a gear. In use the cutter is axially reciprocated and is at the same time turned slowly about its axis. A gear blank A to be cut is placed in operative relationship with the cutter so that the pitch line of the proposed gear tooth lies tangent to the pitch line of the cutter. The blank is turned in unison with two pitch circles roll together. The result of. the reciprocating movement f the cutter combined with the rolling movement between the cutter and'the blank is the'gen eration of properly formed gear teeth on the blank, as indicated in Fig. 1. This method of tooth formation is Well known and further explanation is not needed.

In cutters of this general type, as heretofore constructed, difiiculty has been experienced by reason of the reduction of the pitch diameter when the teeth are sharpened. The teeth must be relieved, and it is obvious that any reduction of the teeth at the cutting faces tends to reduce'the diameter of the cutter. I avoid the difiiculties heretoforeexpressed by making the cutting teeth separate from the body of the cutter and mounting them so that they can be adjusted to compensate for-any tendency toward a decrease of diameter. In the construction,as shown, the teeth are mounted in dovetailed guide grooves 6 formed at regular intervals around These guide grooves are inclined, being parallel to the relief lines which constitute the lateral faces 4, 4 and 5. Itwill be seen that when the teeth are reduced by grinding the cutting faces 3, they can be moved. downward an outward until the original diameter is restored. In grinding care must be taken not to change the angles of the cutting faces.

I preferably provide means for ad u s t1ng all of the teeth simultaneously and in unison, and as shown this means comprises a nut engaging the upper threaded portion of the body 1. This nut contacts withthe upper ends of all of the teeth 2, and when the nut is turned all of the teeth are moved downto mus-suntan.

Patented Oct. 4, 1921...

the cutter so that the be taken to grind all of them to the same lleved teeth each having a cutting face suba set screw 9 adjacehteach tooth. The sevdiameter notwithstanding grinding on the are to be adjusted, and after adjustment-they A circular gear cutter of the axially I of the nut 7 so that the cutter will have the a gear tooth, 'and I ameter and limiting the adjus ment of the 7. A circular gear cutter a v I "1,802,801

ward and outward to the same extent. Pref emeter notwithstanding grinding on the cuterably a lock nut 8 is associatedwith the nut ting faces. I

7 for locki it in place afterthe teeth have A circular gear cutter of the axially. been prope r g adjusted. When the teeth are reciprocating and tooth-curve-gencrating adjusted in unison as described care must type, comprising a circular series of re-' extent, so as to keep their lengths uniformistantially perpendicular to the ax s and Preferably the teeth are ground in'place in each formed at the cuttlng face on its end the body by means of a suitable grinding and at planes of intersection back ofthe machine. v cutting ace with an effective shape corre-- I preferabl provide means supplemental spending to that of a earitooth, and means to the nut 'Ijbr' holding the several teeth in for adjustin the teet in the directions of adjusted positions. This means consists of the lines o relief to maintain the same eral set screws are loosened when the teeth cutting faces. 1 ,80

are tightened to hold the teeth firmly in the reciprocating and tooth-curve-generatin desired sitions. Y type, comprising a circular series of teeth It wil be seen that with my improved each havinga cutting face substantially 'erconstruction theteeth can all'be ground on pendicular to the axis and having straight their cutting faces 3, care being taken to lateral relief faces, each tooth being formed m ntain the rake angle the same. After at the cutting face on its end and at planesthe teeth have all been vground to the same of intersection. ack of the cutting face withextent, they can then be adjusted by means an effective shape corresponding to that of i means for adjusting the 1n1t1al p1tch diameter and the mutual COmteeth in the directions of the straight relief posite contour. If desired, a ring gage such faces to maintain the same diameter notas may be used for determining the di-- withstanding grinding on the cutting faces.

' of the axially teeth. I reciprocating and tooth-curvegneratirig What claim 1s: type, comprising a body, and a circular 1. A. ClIClllitI gear cutter Of the axlally eries of teeth engaging the and adreciprocating and tooth-curve-genei'ating justable along straight lines inclined with extending adju t t g teeth havin tin face on its teeth each having'a cutting face substant th h type, comprising a circular series of radially ft t th axis, each tooth having a cut;

, end substantiall perpen- 100 Contours of s t o f 011 than fi -dicular to the axis and provide with an faces. effective gear-tooth shape and each tooth 2. A circular gear cutter of the toothh in t i ht l t r l r curve-generat ng type, comprislng a clr l lfi ing' in the direction of the corresponding I series of radlally extendlng cutting teeth li f dj t t 4 Bach formed onflits end with i effectlve '8. A circular gear'cutter of the axially p fip g e of a tooth, reciprocating and tooth-curvegenerating and means for adjusting th teefj t type, comprising a body; a clrcular series of taind the same diameter notw thstanding t th g i th b d d dj t bl grin lng.

alon strai ht lines inclined with res ect to 11 3 A circular gear cutter of the axlally the xis, e ch toofth having a cuttin face reclprocatlng and tooth-curve-gcnerat1ng On it d b t ti lly p r ndi fa to" type, comprising a clrcular serles of relieved th axis and provided with an effective gear I p'e and each tooth having straight tially perpendicular to the axis and ea lateral relief faces extendin in the direcformed at the cuttlng face on its en h tion of the corresponding line of adjust a an efl'ectlve shape, COIIBSPOIIdIIIg to that of m, and means carried by the body for a gear tooth, and'meanS-for ad usting h adjusting all of the" teeth in unison. I

circular gear cutter of the axiall stand nggrlndlng n the cu tlug fa reciprocating and tooth-curve-generating 1 l circular gear cutter of the axially retype, comprising a bod c procating and tooth-curve-generatmgtype threaded portion and a lower main portion comprlslng a Serles reli ve provided with a circular series of inclined" teeth each having a cutting face substanguide grooves, a series of teeth re tially perpendicular to the axis and each adjustable alon e giooves formed at the cutting face on its end and each tooth ha g i i at planes of intersection back of the cutting substantially perpendicular to th face withanfeffective shape corresponding provided with an effective gear tooth sha justing the teeth to maintain the same di lief faces extending in the di to that of. a gear tooth, and means for adandfeach tooth having straight lateral rection pf the .11.

corresponding guide groove,

engaging the teeth to adjust them in unison.

10.,A circular gear cutter of the axially reciprocating and. tooth-curvergenerating type, comprising a body having an upper threaded portion and a lower main portion provided with a circular series of inclined guide grooves, a series of teeth respectively adjustable along the said guide grooves, each tooth having a cutting face on its end substantially perpendicular to the afisand provided with an effective gear tooth shape and each tooth having faces extending.

responding guide groove,

threading portio straight lateral relief direction of the cor- 15 a nut fitting the n of the'body and engaging in the the teeth to adjust them in unison, and means supplemental to the nut for locking the several teeth against movement With 20 respect to the b0 In testimony signature.

dy. l v whereof, I hereto affix my WILLARD T. SEARS. 

